There is a great world-wide demand for purified fluids, one of the most commercially important of which is the production of fresh water from salty or brackish water. Aside from distillation techniques, such demand is commonly satisfied by filtration. There are many types of filtration, including reverse osmosis, ultra-filtration and hyper-filtration, and all such technologies are contemplated herein within the generic term, xe2x80x9cfiltration.xe2x80x9d
Most filtration units consists of a can containing a filter, and three flow paths communicating with the outside world. One flow path carries a feed fluid, another flow path carries filtered fluid (i.e., product), and a third flow path carries reject which is sometimes also referred to as waste fluid. In the case of reverse osmosis units used for purifying brackish water, the feed fluid would be the brackish water, the filtered fluid would be desalinated (fresh) water, while the waste fluid would be salty water.
Filtration plants generally include a multitude of physically separate filtration units disposed on or near ground level. The feed, filtered and waste fluids are carried by three separate pipes, respectively, and each filtration unit is fluidly coupled to each of the pipes using a hose or other line. In such embodiments, the entire system is modularized, with the various filtration units comprising the modules. The various modules are mechanically disposed more or less in parallel, and the various membranes are fluidly disposed in parallel. There are many advantages to such an arrangement, not the least of which is that individual modules can be disconnected from the system for service, while the remainder of the system is unaffected.
U.S. Pat. No. 4,125,463 to Chenoweth follows this same strategy, except that his various reverse osmosis modules (called permeator assemblies) are disposed in sets of five about a common riser pipe. This adaptation allows for hundreds of modules to fit conveniently within a single well casing. Here again, however, there is no teaching or suggestion of any sort of super-module which could encompass sets of five RO modules, and which could be arranged serially.
Still other disclosures suggest the creation of a deep underwater housing for containing filtration modules. Once again, the modules are contemplated to be physically disposed more or less in parallel, while the filters are contemplated to be fluidly disposed in parallel.
The known arrangements of modules are not, however, without their limitations. Positioning of modules in parallel requires considerable space, and when placed on land in a commercial embodiment often requires a relatively large xe2x80x9cfootprint.xe2x80x9d The Chenoweth type concept of using a deep well makes relatively good use of space, but is impractical because of the vast number of interconnections required.
In the present invention apparatus and methods are provided in which filter containing production modules are mechanically coupled in series, while the filters contained in the production modules are fluidly coupled with the feed, filtered and waste fluid flowpaths in parallel.
Among the many different possibilities contemplated, each production module may advantageously contain not only a filter, but all three flowpaths, so that a series of coupled modules can be installed, accessed, and removed as a single unit. It is further contemplated that coupled modules may be deployed in space efficient manner, such as by insertion into a deep or shall well, a tower, along the ground, into the side of a hill or mountain, or even under a road or parking lot. It is still ether contemplated that adjacent production modules may be designed to mate with one another using a slip fit joint, and that the production modules may be maintained in mating relationship through connections to supporting cables or rods.